Device for use in connection with metal extrusion presses along a press path

ABSTRACT

A conveying arrangement for supporting workmembers of an elongated nature which pass in a longitudinal direction through a work station and which emerge from the work station in such condition as to be capable of being damaged upon physical contact. The conveying arrangement consists of a guideway extending longitudinally beneath the emerging workmember and having upwardly directed air nozzles distributed longitudinally and laterally thereof and establishing an upwardly moving air body which engages the workmember from below and flows around the workmember and guides and supports the workmember thereby preventing physical contact between the workmember and the guideway.

United States Patent 11 1 Raab 1 Dec. 16, 1975 1 DEVICE FOR USE IN CONNECTION WITH METAL EXTRUSION PRESSES ALONG A PRESS PATH [75] inventor: Richard Raab, Rothenbach, Germany [73] Assignee: Diehl, Nuremberg, Germany [22] Filed: June 19, 1974 [21] Appl. No: 480,729

Related US. Application Data [63] Continuation of Ser. No. 267,038, June 28, 1972.

abandoned.

[52] US. Cl. 72/24 [51] Int. Cl. B21J 7/46; B21B 31/07 [58] Field of Search 72/24, 38, 257, 426, 342,

[56] References Cited UNITED STATES PATENTS 9/1908 Norton 302/31 X Lyon 72/24 3,350,140 10/1967 Strydom 302/31 Primary E.ranzinerLanham. C. W. Assistant E.\'aminerR0bert M. Rogers Attorney, Agent, or FirmWalter Becker [57] ABSTRACT A conveying arrangement for supporting workmembers of an elongated nature which pass in a longitudinal direction through a work station and which emerge from the work station in such condition to be capable of being damaged upon physical contact. The conveying arrangement consists of a guideway extending longitudinally beneath the emerging workmember and having upwardly directed air nozzles distributed longitudinally and laterally thereof and establishing an upwardly moving air body which engages the workmember from below and flows around the workmember and guides and supports the workmem ber thereby preventing physical contact between the workmember and the guideway.

5 Claims, 10 Drawing Figures US. Patent Dec. 16,1975 Sheetl 01 3 3,926,022

Fig. 1

Fig. 2

U.S. Patent Dec. 16,1975 Sheet20f3 3,926,022

U2 Fig.6 1

EIIZI EII [IE 5 US. Patent Dec. 16, 1975 Sheet 3 of 3 3,926,022

lll/I/Itl 1 E ie 1 II Ba a DEVICE FOR USE IN CONNECTION WITH METAL EXTRUSllON PRESSES ALONG A PRESS PATH This is a continuation of application Ser. No.

267,038, filed June 28, 1972 and now abandoned.

The present invention relates to a device for use in connection with metal extrusion presses, especially pipe extrusion presses, located along a press path, which device is provided with means for cooling the extruded strand and for preventing damage to surfaces thereof by friction on the press path.

The press path of horizontal metal extrusion presses customarily has at the bottom as well as on the sides a lining of gray cast iron or other substances for reducing the friction along the path. The extruded strand slides along in the bed of the press path while its surface is easily damaged, especially after being extruded from the matrix of the extrusion press, i.e., at a time when it is still soft and therefore very sensitive. In order to reduce the movement of the strand relative to the press path, it is known instead of a fixed press path to provide a plate band or belt which is movable in the direction in which the pressing is effected. Since, however, an abso lute acceleration and braking of the plate band in conformity with the speed is hardly possible in conformity with the strand, also in this instance certain surface damage such as grinding, grooves, scratches, and impressions occur. This damage will, during the later drawing of the strand be partly reduced but not completely eliminated. During the polishing and galvanic treatment, the damage causes holes and grooves. Occasionally, pipes will, during the extrusion pressing, also get curved, which means that they bend in the warm plastic condition and after cooling off are not straight.

The possible extrusion press length, primarily with thinwalled pipes is limited not only by the capacity of the recipent of the extrusion press but above all by the back accumulation of the outgoing strand. Finally, during the manufacture of pipes from non-board blocks, at the head of the pipe there occurs also a full profile prop which is caused by the fact that the block in the receiver of the extrusion press is punched by the pressing mandrel. Above all, with thin and therefore particularly sensitive pipes, this prop usually remains directly behind the matrix. The outgoing pipe strand grazes or brushes along said prop, sometimes takes it along while the roller and in this way a more or less considerable section is damaged.

It is, therefore, an object of the invention to provide the press path of a horizontal metal extrusion press with a device which will overcome the above mentioned drawbacks and will prevent friction tracks, bending, or flattening of the pipe and will reduce all mechanical contact, at least until the surface of the strand has solidified to a required minimum extent.

These and other objects and advantages of the invention will appear more clearly from the following specification, in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatical side view of a horizontal metal extrusion press and also shows the adjacent press path with a device according to the invention.

FIG. la is a schematic side view of the press path according to FIG. 1 subdivided into several segments with air blowing jets or nozzles inclined in conveying direction and showing a pipe suspended over the first segment.

taken along the line III-III of FIG. 1. IO

FIGS. 4 and 5 illustrate the supporting and stabilizing functions of the device according to the invention.

FIG. 6 is a control circuit for controlling the air nozzle means.

FIG. 6a is a schematic side view similar to that of FIG. la showing valve shift means arranged in the air supply passages of the individual segments and having a pipe suspended over the first segment.

FIG. 6b is a view corresponding to that of FIG. 6a with a pipe in transition from the first segment to the second segment.

The device according to the present invention is characterized primarily in that the press path, at least over a portion of its length, is provided with one or more rows of air nozzles through which for the duration of the extrusion operation air is pressed from below against the strand being extruded from the matrix of the extrusion press, said air being blown against said strand at a pressure which lifts the strand off the press path or holds and/or guides the strand in a floating manner. If desired, two or more, preferably three rows of air nozzles may be provided which are of a round or slit shape. In order to permit a fast removal of the prop which is formed at the head of a pipe strand during the perforation of a non-board block by the press mandrel in the receiver, the side walls of the press path may be interrupted at least shortly behind the extrusion press. The air nozzles are inclined primarily toward a common central axis in which the strand floats during the pressing operation and as the case may be also in the transporting direction of the strand. Inasmuch as the extrusion operation itself lasts only a short time, the air nozzles may be in conformity with the discharge of the strand from the extrusion press or its forward transport over the press path be adapted to be turned on sectionwise one after another.

By means of the device according to the invention the strand is grasped immediately after it leaves the extrusion press and stabilized in axial direction is carried on an air jet bundle, or an air cushion path.

In this connection, it may be mentioned that a supporting and/or slow transporting of band material on a cushion of highly heated gases is known in connection with a glowing furnace. In this instance, a plurality of nozzles distributed over the entire surface carry the material resting ahead of and/or behind the furnace on a reel in a gas-cushioned way while corresponding additional nozzles acting from above assure a height stabilizing passage of the band, prevent an upward bending of the material to be heated and simultaneously heat the same also from above.

In contrast thereto, the device according to the present invention is intended not only to carry a strand leaving the matrix at a speed of a plurality of meters per secq d, but is also intended possibly without resorting to abutment means, to stabilize the strand being extruded to the rated axis and to cool the same at the surface. The device is suitable for all round profiles, especially thin-walled pipes. The air flows upwardly on the 3 left and right-hand side of the strand. Thus, a suction occurs which returns the laterally deviating strand al ways to the rated axis. Theoretically, the present invention permits an extrusion of pipes of any desired length.

When dealing'with flat and other profile strands, by means of the device according to the invention, it is possible to obtain an air cusion-like support or-a certain weight relief so that no grinding tracks will form in the surface of the strand. The lateral guiding will be assured above all by lateral sliding rollers or side walls of the press path, whereas with round and in particular pipe profiles, the side walls of the press path merely have a safety effect in case of tears.

Referring now to the drawings in detail, FIG. 1 diagrammatically shows a horizontal metal extrusion press 1, and a carriage 2 which carries a press-way 3. The side walls 4, 5 of said pressway 3 are shortly behind the extrusion press I removed for a few yards.

As will be seen from FIG. 2, a bottom plate 6 of the pressway 3 is provided with a plurality of rows of bores 7 which serve an air nozzles and if desired may be slotshaped.

The press-way 3 according to FIG. la provides a series or row of upwardly directed air nozzle means 7a, 7b, 7c grouped together as illustrated. The air that streams out of these nozzle means supports a pipe 10.

When the pipe passes over from the first air nozzle segment into the following segment, air likewise blows out of the nozzles 7b engaging the pipe 10 from below and maintaining the pipe I0 in suspension. The inclination of the air nozzles 70, 7b, 7c conveys to the pipe 10 in addition to the lift also a weak propelling force.

As shown in FIG. 2 there is a bottom plate 60f the press-way 3 provided with several rows of such bores respectively air nozzles 7. According to FIG. 3 there is an air chamber 8 provided below the bottom plate 6 which becomes supplied from an air pressure conduit 9 by way of a non-illustrated pressure reducing valve. The nozzle bores 7 are inclined toward the middle axis as apparent from the indicated air stream and the pipe 10 is kept suspended in this manner.

According to FIG. 3, below the bottom plate 6 there is provided an air chamber 8 which is fed with compressed air from an air pressure conduit 9 through a non-illustrated pressure reducing valve. As will be evident from the indicated air flow, the bores 7' and '7" are inclined toward the central axis and here keep a pipe strand l0 floating.

In a manner shown by FIGS. la and lb, the air nozzle means 7a, 7b and 70 may additionally be inclined in the transporting direction for the extruded articles.

As will be seen from FIG. 4, the air currents, the diameters of which are small in comparison to the pipe 10 to be supported, rest rather long against the surface of the body of the round profile and tear off uniformly above the latter.

If, as illustrated in FIG. 5, pipe 10 deviates to one side, the longer path on one side and the underpressure caused thereby will, at this point, relative to the underpressure on the opposite side bring about a stabilizing power component which means that the air flow returns the pipe 10 to its central position.

Inasmuch as the extrusion operation, i.e., the time period in which the extrusion material extrudes upon the press-way 3 is rather short relative to the total time period between the pressing operations, the air nozzles 7 are not continuously turned on, nor are all air nozzles simultaneously turned on. Therefore, the air chamber 8 is closed with regard to the bores 7 serving as air nozzles. This closure is effected section-wise by nonillustrated magnetic valves. These valves are each step-wise opened when the strand 10 runs off and are closed again as soon as the strand 10 comes to a standstill and is cooled at its surface.

The control of the above described device is effected primarily in conformity with the pressing pressure of the metal extrusion press I, for instance through the in tervention of a control chain or sequence as is illustrated in a simplified manner by the circuit of FIG. 6; more particularly, FIG. 6a shows that the control is effected by way of valve switches or shift means 5,, S S which are arranged between the air pressure conduit 9 and the individual segments 8a, 8b, 8c of the air chamber 8. By way of the valve shift means S, the air chamber 8a is supplied with air from the air pressure conduit 9. The air that streams out of the air nozzles 7a supports the pipe or strand 10 over the first segment. In the second segment the switch or valve shift means S is located between the air pressure conduit 9 and the air chamber 8. When the strand 10 shifts over into the second segment, the air that streams out of the air nozzles 7b keeps the strand 10 in suspension while simultaneously cooling the strand on all sides thereof. In the same manner the switch or valve shift means S is effective, and further segments are built-up in an analogous manner. Through the intervention of a switch U voltage may be placed on a transformer T. Through the intervention of a switch U a relay chain is supplied with current, whereas through a switch U a magnet valve control chain is supplied with current. The device also comprises a limit switch E and a manometer controlled switch P V V are delayed time relays with their pertaining contacts v v A, B are heavy duty switches through which contact a a a and b b b;;, may be energized. S S represent the above mentioned magnetic valves for controlling the air nozzles 7 (FIG. 2) and including 7a, 7b, 7c as to the air pressure conduit 9. The control course will, after closing the contacts U U U be as follows:

The pressing pressure of the inwardly moving extrusion press plunger closes the switch p through a contact manometer P. E is closed already at rest. V receives voltage and with a time delay closes the contact v in the circuit of the heavy duty switch A. The heavy duty switch A closes the self-holding switch a and furthermore through contact switch a closes the delayed time relay V and also through switch a closes the magnetic valve S for the first section 8a of the air nozzles 7a. Now the relay V will with a certain predetermined or adjusted time relay close the switch v Through the latter, the heavy duty switch B receives current and closes the switches, b b h The switch b is intended for the next following time relay V not shown in the drawings. The switch b conveys current to the magnetic valve S which in the second section connects the air nozzle 76 to the air pressure conduit 9. When up to the end all air valves are open and the strand 10 is pressed out in its entire length, the limit switch E turns off the heavy duty switches A, B, Thereupon also the magnets S S become deenergized and close the passages from the air chamber 8 pressure conduit 9 to the air chamber 8a, 8b, 8c, and the air nozzles 70, 7b, 70, thereof. The strand 10 lowers itself onto the bed of the press-way 3. Since on one hand the prop could during the extrusion process drop toward the side in that portion of the press-way 3 where the lateral walls 4, 5 are lacking, and since on the other hand with the completion of the extrusion process, the longitudinal displacement of the strand is completed and its surface is sufficiently hard in view of the intersive air cooling, the strand 10 will no longer be damaged when it lowers itself onto the bed path of the press-way 3. Instead of a time control as illustrated in FIG. 6, it is, of course also possible to employ a photoelectric or thermoelectric control in conformity with the forward moving strand.

The preceding paragraphs describe primarily the employment of the strand discharge and stabilization by the air current in connection with round profiles. Depending on the diameter and weight of the strand or unit of length, it is expedient to arrange two, three, or more rows of nozzles 7 adjacent to each other. Similarly, the spacing between the nozzles 7 in pressing direction which with a nozzle diameter of one millimeter and two rows may amount to up to fifty millimeters is to be adapted to the respective dimensions and coefficients of the material. The same applies to the air pressure which may amount, for instance, from I to 1.8 atmospheres above atmospheric pressure.

With flat strand material, as for instance, flat bars, bands, and the like, the air current of the nozzles 7 is suitable also to assure a lateral guiding, but only when employing separate control means. In each instance, however, the air current permits an air cushion-like support of the flat material at reduced pressure, slightly above the base plate of the press-way, while the lateral guiding is effected primarily by the side walls 4, 5, or by lateral sliding rollers, not shown in the drawings.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings, but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. In combination with a horizontal extrusion press for extruding heated, softened, tubular articles, a device aligned with said press below its axis for conveying extruded, elongated, tubular articles from said press in which a tubular articles passes over a press-way receiving an article from said press, said press-way having a plurality of nozzles spaced longitudinally along said press-way and directed generally upwardly, air supply means connected to said nozzles to supply air under pressure to said nozzles and to form upwardly directed jets of air against the under side of a tubular articles passing along said press-way, said upwardly directed jets of air cooling and hardening said extruded articles and maintaining it centered in said press-way during its passage.

2. In a device in combination with an extrusion press, as claimed in claim 1, in which said nozzles are confined to a narrow, longitudinal zone underlying said article as it passes along said press-way, said zone being of no greater width than said article extruded by said press with said nozzles arranged symmetrically on opposite sides of the vertical axial plane of said press-way, so that said article overlies said jets to cause the air to pass around the sides of said article and maintain said article centered along the axis of said press.

3. A device according to claim 1 in which said nozzle means are arranged in at least two laterally spaced rows on opposite sides of the vertical plane in which the tubular articles move, the nozzle means of each said row being inclined inwardly toward said plane.

4. A device according to claim I in which said nozzle means are arranged in at least two laterally spaced rows on opposite sides of the vertical plane in which the workmember moves, the nozzle means of each said row being inclined inwardly toward said plane and are furthermore inclined in the direction of movement of the tubular articles.

5. A device according to claim I in which said nozzle means are grouped in longitudinal sections with the sections in end to end relation, and control means operable to bring about the supply of air under pressure to the nozzle means of the respective sections sequentially in the direction of movement of said tubular articles. 

1. In combination with a horizontal extrusion press for extruding heated, softened, tubular articles, a device aligned with said press below its axis for conveying extruded, elongated, tubular articles from said press in which a tubular articles passes over a press-way receiving an article from said press, said press-way having a plurality of nozzles spaced longitudinally along said press-way and directed generally upwardly, air supply means connected to said nozzles to supply air under pressure to said nozzles and to form upwardly directed jets of air against the under side of a tubular articles passing along said press-way, said upwardly directed jets of air cooling and hardening said extruded articles and maintaining it centered in said press-way during its passage.
 2. In a device in combination with an extrusion press, as claimed in claim 1, in which said nozzles are confined to a narrow, longitudinal zone underlying said article as it passes along said press-way, said zone being of no greater width than said article extruded by said press with said nozzles arranged symmetrically on opposite sides of the vertical axial plane of said press-way, so that said article overlies said jets to cause the air to pass around the sides of said article and maintain said article centered along the axis of said press.
 3. A device according to claim 1 in which said nozzle means are arranged in at least two laterally spaced rows on opposite sides of the vertical plane in which the tubular articles move, the nozzle means of each said row being inclined inwardly toward said plane.
 4. A device according to claim 1 in which said nozzle means are arranged in at least two laterally spaced rows on opposite sides of the vertical plane in which the workmember moves, the nozzle means of each said row being inclined inwardly toward said plane and are furthermore inclined in the direction of movement of the tubular articles.
 5. A device according to claim 1 in which said nozzle means are grouped in longitudinal sections with the sectionS in end to end relation, and control means operable to bring about the supply of air under pressure to the nozzle means of the respective sections sequentially in the direction of movement of said tubular articles. 